The present invention is generally directed to a particulate material, and more particularly to a multifunctional particulate material, composition, and fluid capable of exhibiting one or more properties, such as magnetic, thermal, optical, electrical, biological, lubrication and rheological.
Dispersions of particles in fluids, termed as functional fluids, exhibit controllable property changes with an application of either one or a combination of electrical, thermal, optical or magnetic impulses. The prominent examples from the art, include thermal heat transfer fluids, magnetorheological (MR) fluids and electrorheological (ER) fluids. ER and MR fluids are known to exhibit changes in rheological behavior in the presence of an electrical and magnetic field, respectively, making them useful in a wide spectrum of applications, such as brakes, clutches, dampers and many others. However, if these fluids could exhibit more than one functionality, their performance and life would increase many-folds. For example, if MR fluids, in addition to Theological control, have a thermal tunablity, the life of the device, which is adversely affected by the dissipated heat, can be significantly increased. Such multifunctional fluids are not known to exist presently.
Various examples of prior art in this area include U.S. Pat. Nos. 3,047,507; 3,937,839; 4,064,409; 4,106,488; 4,107,288; 4,183,156; 4,219,945; 4,267,234; 4,268,413; 4,303,636; 4,323,056; 4,340,626; 4,342,157; 4,443,430; 4,452,773; 4,454,234; 4,472,890; 4,501,726; 4,545,368; 4,554,088; 4,574,782; 4,613,304; 4,628,037; 4,637,394; 4,662,359; 4,672,040; 4,695,392; 4,695,393; 4,721,618; 4,992,190; 4,999,188; 5,067,952; 5,108,359; 5,161,776; 5,180,583; 5,202,352; 5,207,675; 5,236,410; 5,354,488; 5,358,659; 5,374,246; 5,427,767; 5,466,609; 5,493,792; 5,507,744; 5,525,249; 5,565,215; 5,582,425; 5,595,735; 5,597,531; 5,624,685; 5,635,162; 5,635,215; 5,645,849; 5,646,185; 5,667,715; 5,670,078; 5,695,480; 5,702,630; 5,707,078; 5,714,829; 5,782,954; 5,800,372; 5,900,184; 5,927,753; 5,947,514; 6,027,664; 6,036,226; 6,036,955; 6,039,347; 6,044,866; 6,051,607; 6,076,852; 6,096,021; 6,149,576; 6,149,832; 6,167,313; 6,186,176 B1; 6,189,538 B1; 6,266,897 B1; 6,274,121 B1; 6,299,619 B1; 6,315,709 B1; 6,335,384 B1; 6,355,275 B1; 6,399,317 B1 6,409,851 B1; US 2001/0016210 A1; US 2001/0033384 and US 2002/0045045 A1; and.